Current limiting circuit interruption devices such as that described within U.S. Pat. No. 4,375,021 require a large separation distance between the circuit breaker contacts that become electrodynamically repulsed upon short circuit overcurrent conditions. The increased contact separation distance further requires a longer handle stroke to move the circuit breaker operating handle between its "ON" and "OFF" positions. However, the placement of an electronic trip unit and selected circuit breaker accessories in the circuit breaker cover as described within U.S. Pat. No. 4,507,527 limits the circuit breaker operating handle path. It would be advantageous therefore to over-center the circuit breaker operating mechanism springs in the shortest operating handle path to optimize the transfer of the circuit breaker contacts between their "OFF" and "ON" positions, in the shortest distance of travel of the circuit breaker operating handle.
U.S. Pat. No. 3,002,068 describes a bail that is pivotally attached to the circuit breaker operating handle yoke to assist the operating springs in moving to their over-center position. The pivotal arrangement of the bail requires a pair of guides on the operating mechanism side frames to position the bail with respect to the cradle linkage. It is believed that the bail and guides can be eliminated by simplified means integrally-formed with the operating handle yoke to effect an efficient and inexpensive over-center accelerator for the operating mechanism springs.
One purpose of the instant invention is to provide a simple and economic over-center accelerator function to the circuit breaker operating handle to rapidly drive the operating mechanism springs to their over-center positions in the early stages of the circuit breaker operating handle stroke.